import {
  AmbientLight,
  AnimationClip,
  Bone,
  BufferGeometry,
  ClampToEdgeWrapping,
  Color,
  DirectionalLight,
  EquirectangularReflectionMapping,
  Euler,
  FileLoader,
  Float32BufferAttribute,
  Group,
  Line,
  LineBasicMaterial,
  Loader,
  LoaderUtils,
  MathUtils,
  Matrix3,
  Matrix4,
  Mesh,
  MeshLambertMaterial,
  MeshPhongMaterial,
  NumberKeyframeTrack,
  Object3D,
  OrthographicCamera,
  PerspectiveCamera,
  PointLight,
  PropertyBinding,
  Quaternion,
  QuaternionKeyframeTrack,
  RepeatWrapping,
  Skeleton,
  SkinnedMesh,
  SpotLight,
  sRGBEncoding,
  Texture,
  TextureLoader,
  Uint16BufferAttribute,
  Vector3,
  Vector4,
  VectorKeyframeTrack
} from '../../three.module.js';
import * as fflate from '../libs/fflate.module.js';
import {NURBSCurve} from '../curves/NURBSCurve.js';

/**
 * Loader loads FBX file and generates Group representing FBX scene.
 * Requires FBX file to be >= 7.0 and in ASCII or >= 6400 in Binary format
 * Versions lower than this may load but will probably have errors
 *
 * Needs Support:
 *  Morph normals / blend shape normals
 *
 * FBX format references:
 *  https://help.autodesk.com/view/FBX/2017/ENU/?guid=__cpp_ref_index_html (C++ SDK reference)
 *
 * Binary format specification:
 *  https://code.blender.org/2013/08/fbx-binary-file-format-specification/
 */


let fbxTree;
let connections;
let sceneGraph;

class FBXLoader extends Loader {

  constructor(manager) {

    super(manager);

  }

  load(url, onLoad, onProgress, onError) {

    const scope = this;

    const path = (scope.path === '') ? LoaderUtils.extractUrlBase(url) : scope.path;

    const loader = new FileLoader(this.manager);
    loader.setPath(scope.path);
    loader.setResponseType('arraybuffer');
    loader.setRequestHeader(scope.requestHeader);
    loader.setWithCredentials(scope.withCredentials);

    loader.load(url, function (buffer) {

      try {

        onLoad(scope.parse(buffer, path));

      } catch (e) {

        if (onError) {

          onError(e);

        } else {

          console.error(e);

        }

        scope.manager.itemError(url);

      }

    }, onProgress, onError);

  }

  parse(FBXBuffer, path) {

    if (isFbxFormatBinary(FBXBuffer)) {

      fbxTree = new BinaryParser().parse(FBXBuffer);

    } else {

      const FBXText = convertArrayBufferToString(FBXBuffer);

      if (!isFbxFormatASCII(FBXText)) {

        throw new Error('THREE.FBXLoader: Unknown format.');

      }

      if (getFbxVersion(FBXText) < 7000) {

        throw new Error('THREE.FBXLoader: FBX version not supported, FileVersion: ' + getFbxVersion(FBXText));

      }

      fbxTree = new TextParser().parse(FBXText);

    }

    // console.log( fbxTree );

    const textureLoader = new TextureLoader(this.manager).setPath(this.resourcePath || path).setCrossOrigin(this.crossOrigin);

    return new FBXTreeParser(textureLoader, this.manager).parse(fbxTree);

  }

}

// Parse the FBXTree object returned by the BinaryParser or TextParser and return a Group
class FBXTreeParser {

  constructor(textureLoader, manager) {

    this.textureLoader = textureLoader;
    this.manager = manager;

  }

  parse() {

    connections = this.parseConnections();

    const images = this.parseImages();
    const textures = this.parseTextures(images);
    const materials = this.parseMaterials(textures);
    const deformers = this.parseDeformers();
    const geometryMap = new GeometryParser().parse(deformers);

    this.parseScene(deformers, geometryMap, materials);

    return sceneGraph;

  }

  // Parses FBXTree.Connections which holds parent-child connections between objects (e.g. material -> texture, model->geometry )
  // and details the connection type
  parseConnections() {

    const connectionMap = new Map();

    if ('Connections' in fbxTree) {

      const rawConnections = fbxTree.Connections.connections;

      rawConnections.forEach(function (rawConnection) {

        const fromID = rawConnection[0];
        const toID = rawConnection[1];
        const relationship = rawConnection[2];

        if (!connectionMap.has(fromID)) {

          connectionMap.set(fromID, {
            parents: [],
            children: []
          });

        }

        const parentRelationship = {ID: toID, relationship: relationship};
        connectionMap.get(fromID).parents.push(parentRelationship);

        if (!connectionMap.has(toID)) {

          connectionMap.set(toID, {
            parents: [],
            children: []
          });

        }

        const childRelationship = {ID: fromID, relationship: relationship};
        connectionMap.get(toID).children.push(childRelationship);

      });

    }

    return connectionMap;

  }

  // Parse FBXTree.Objects.Video for embedded image data
  // These images are connected to textures in FBXTree.Objects.Textures
  // via FBXTree.Connections.
  parseImages() {

    const images = {};
    const blobs = {};

    if ('Video' in fbxTree.Objects) {

      const videoNodes = fbxTree.Objects.Video;

      for (const nodeID in videoNodes) {

        const videoNode = videoNodes[nodeID];

        const id = parseInt(nodeID);

        images[id] = videoNode.RelativeFilename || videoNode.Filename;

        // raw image data is in videoNode.Content
        if ('Content' in videoNode) {

          const arrayBufferContent = (videoNode.Content instanceof ArrayBuffer) && (videoNode.Content.byteLength > 0);
          const base64Content = (typeof videoNode.Content === 'string') && (videoNode.Content !== '');

          if (arrayBufferContent || base64Content) {

            const image = this.parseImage(videoNodes[nodeID]);

            blobs[videoNode.RelativeFilename || videoNode.Filename] = image;

          }

        }

      }

    }

    for (const id in images) {

      const filename = images[id];

      if (blobs[filename] !== undefined) images[id] = blobs[filename];
      else images[id] = images[id].split('\\').pop();

    }

    return images;

  }

  // Parse embedded image data in FBXTree.Video.Content
  parseImage(videoNode) {

    const content = videoNode.Content;
    const fileName = videoNode.RelativeFilename || videoNode.Filename;
    const extension = fileName.slice(fileName.lastIndexOf('.') + 1).toLowerCase();

    let type;

    switch (extension) {

      case 'bmp':

        type = 'image/bmp';
        break;

      case 'jpg':
      case 'jpeg':

        type = 'image/jpeg';
        break;

      case 'png':

        type = 'image/png';
        break;

      case 'tif':

        type = 'image/tiff';
        break;

      case 'tga':

        if (this.manager.getHandler('.tga') === null) {

          console.warn('FBXLoader: TGA loader not found, skipping ', fileName);

        }

        type = 'image/tga';
        break;

      default:

        console.warn('FBXLoader: Image type "' + extension + '" is not supported.');
        return;

    }

    if (typeof content === 'string') { // ASCII format

      return 'data:' + type + ';base64,' + content;

    } else { // Binary Format

      const array = new Uint8Array(content);
      return window.URL.createObjectURL(new Blob([array], {type: type}));

    }

  }

  // Parse nodes in FBXTree.Objects.Texture
  // These contain details such as UV scaling, cropping, rotation etc and are connected
  // to images in FBXTree.Objects.Video
  parseTextures(images) {

    const textureMap = new Map();

    if ('Texture' in fbxTree.Objects) {

      const textureNodes = fbxTree.Objects.Texture;
      for (const nodeID in textureNodes) {

        const texture = this.parseTexture(textureNodes[nodeID], images);
        textureMap.set(parseInt(nodeID), texture);

      }

    }

    return textureMap;

  }

  // Parse individual node in FBXTree.Objects.Texture
  parseTexture(textureNode, images) {

    const texture = this.loadTexture(textureNode, images);

    texture.ID = textureNode.id;

    texture.name = textureNode.attrName;

    const wrapModeU = textureNode.WrapModeU;
    const wrapModeV = textureNode.WrapModeV;

    const valueU = wrapModeU !== undefined ? wrapModeU.value : 0;
    const valueV = wrapModeV !== undefined ? wrapModeV.value : 0;

    // http://download.autodesk.com/us/fbx/SDKdocs/FBX_SDK_Help/files/fbxsdkref/class_k_fbx_texture.html#889640e63e2e681259ea81061b85143a
    // 0: repeat(default), 1: clamp

    texture.wrapS = valueU === 0 ? RepeatWrapping : ClampToEdgeWrapping;
    texture.wrapT = valueV === 0 ? RepeatWrapping : ClampToEdgeWrapping;

    if ('Scaling' in textureNode) {

      const values = textureNode.Scaling.value;

      texture.repeat.x = values[0];
      texture.repeat.y = values[1];

    }

    return texture;

  }

  // load a texture specified as a blob or data URI, or via an external URL using TextureLoader
  loadTexture(textureNode, images) {

    let fileName;

    const currentPath = this.textureLoader.path;

    const children = connections.get(textureNode.id).children;

    if (children !== undefined && children.length > 0 && images[children[0].ID] !== undefined) {

      fileName = images[children[0].ID];

      if (fileName.indexOf('blob:') === 0 || fileName.indexOf('data:') === 0) {

        this.textureLoader.setPath(undefined);

      }

    }

    let texture;

    const extension = textureNode.FileName.slice(-3).toLowerCase();

    if (extension === 'tga') {

      const loader = this.manager.getHandler('.tga');

      if (loader === null) {

        console.warn('FBXLoader: TGA loader not found, creating placeholder texture for', textureNode.RelativeFilename);
        texture = new Texture();

      } else {

        loader.setPath(this.textureLoader.path);
        texture = loader.load(fileName);

      }

    } else if (extension === 'psd') {

      console.warn('FBXLoader: PSD textures are not supported, creating placeholder texture for', textureNode.RelativeFilename);
      texture = new Texture();

    } else {

      texture = this.textureLoader.load(fileName);

    }

    this.textureLoader.setPath(currentPath);

    return texture;

  }

  // Parse nodes in FBXTree.Objects.Material
  parseMaterials(textureMap) {

    const materialMap = new Map();

    if ('Material' in fbxTree.Objects) {

      const materialNodes = fbxTree.Objects.Material;

      for (const nodeID in materialNodes) {

        const material = this.parseMaterial(materialNodes[nodeID], textureMap);

        if (material !== null) materialMap.set(parseInt(nodeID), material);

      }

    }

    return materialMap;

  }

  // Parse single node in FBXTree.Objects.Material
  // Materials are connected to texture maps in FBXTree.Objects.Textures
  // FBX format currently only supports Lambert and Phong shading models
  parseMaterial(materialNode, textureMap) {

    const ID = materialNode.id;
    const name = materialNode.attrName;
    let type = materialNode.ShadingModel;

    // Case where FBX wraps shading model in property object.
    if (typeof type === 'object') {

      type = type.value;

    }

    // Ignore unused materials which don't have any connections.
    if (!connections.has(ID)) return null;

    const parameters = this.parseParameters(materialNode, textureMap, ID);

    let material;

    switch (type.toLowerCase()) {

      case 'phong':
        material = new MeshPhongMaterial();
        break;
      case 'lambert':
        material = new MeshLambertMaterial();
        break;
      default:
        console.warn('THREE.FBXLoader: unknown material type "%s". Defaulting to MeshPhongMaterial.', type);
        material = new MeshPhongMaterial();
        break;

    }

    material.setValues(parameters);
    material.name = name;

    return material;

  }

  // Parse FBX material and return parameters suitable for a three.js material
  // Also parse the texture map and return any textures associated with the material
  parseParameters(materialNode, textureMap, ID) {

    const parameters = {};

    if (materialNode.BumpFactor) {

      parameters.bumpScale = materialNode.BumpFactor.value;

    }

    if (materialNode.Diffuse) {

      parameters.color = new Color().fromArray(materialNode.Diffuse.value);

    } else if (materialNode.DiffuseColor && (materialNode.DiffuseColor.type === 'Color' || materialNode.DiffuseColor.type === 'ColorRGB')) {

      // The blender exporter exports diffuse here instead of in materialNode.Diffuse
      parameters.color = new Color().fromArray(materialNode.DiffuseColor.value);

    }

    if (materialNode.DisplacementFactor) {

      parameters.displacementScale = materialNode.DisplacementFactor.value;

    }

    if (materialNode.Emissive) {

      parameters.emissive = new Color().fromArray(materialNode.Emissive.value);

    } else if (materialNode.EmissiveColor && (materialNode.EmissiveColor.type === 'Color' || materialNode.EmissiveColor.type === 'ColorRGB')) {

      // The blender exporter exports emissive color here instead of in materialNode.Emissive
      parameters.emissive = new Color().fromArray(materialNode.EmissiveColor.value);

    }

    if (materialNode.EmissiveFactor) {

      parameters.emissiveIntensity = parseFloat(materialNode.EmissiveFactor.value);

    }

    if (materialNode.Opacity) {

      parameters.opacity = parseFloat(materialNode.Opacity.value);

    }

    if (parameters.opacity < 1.0) {

      parameters.transparent = true;

    }

    if (materialNode.ReflectionFactor) {

      parameters.reflectivity = materialNode.ReflectionFactor.value;

    }

    if (materialNode.Shininess) {

      parameters.shininess = materialNode.Shininess.value;

    }

    if (materialNode.Specular) {

      parameters.specular = new Color().fromArray(materialNode.Specular.value);

    } else if (materialNode.SpecularColor && materialNode.SpecularColor.type === 'Color') {

      // The blender exporter exports specular color here instead of in materialNode.Specular
      parameters.specular = new Color().fromArray(materialNode.SpecularColor.value);

    }

    const scope = this;
    connections.get(ID).children.forEach(function (child) {

      const type = child.relationship;

      switch (type) {

        case 'Bump':
          parameters.bumpMap = scope.getTexture(textureMap, child.ID);
          break;

        case 'Maya|TEX_ao_map':
          parameters.aoMap = scope.getTexture(textureMap, child.ID);
          break;

        case 'DiffuseColor':
        case 'Maya|TEX_color_map':
          parameters.map = scope.getTexture(textureMap, child.ID);
          if (parameters.map !== undefined) {

            parameters.map.encoding = sRGBEncoding;

          }

          break;

        case 'DisplacementColor':
          parameters.displacementMap = scope.getTexture(textureMap, child.ID);
          break;

        case 'EmissiveColor':
          parameters.emissiveMap = scope.getTexture(textureMap, child.ID);
          if (parameters.emissiveMap !== undefined) {

            parameters.emissiveMap.encoding = sRGBEncoding;

          }

          break;

        case 'NormalMap':
        case 'Maya|TEX_normal_map':
          parameters.normalMap = scope.getTexture(textureMap, child.ID);
          break;

        case 'ReflectionColor':
          parameters.envMap = scope.getTexture(textureMap, child.ID);
          if (parameters.envMap !== undefined) {

            parameters.envMap.mapping = EquirectangularReflectionMapping;
            parameters.envMap.encoding = sRGBEncoding;

          }

          break;

        case 'SpecularColor':
          parameters.specularMap = scope.getTexture(textureMap, child.ID);
          if (parameters.specularMap !== undefined) {

            parameters.specularMap.encoding = sRGBEncoding;

          }

          break;

        case 'TransparentColor':
        case 'TransparencyFactor':
          parameters.alphaMap = scope.getTexture(textureMap, child.ID);
          parameters.transparent = true;
          break;

        case 'AmbientColor':
        case 'ShininessExponent': // AKA glossiness map
        case 'SpecularFactor': // AKA specularLevel
        case 'VectorDisplacementColor': // NOTE: Seems to be a copy of DisplacementColor
        default:
          console.warn('THREE.FBXLoader: %s map is not supported in three.js, skipping texture.', type);
          break;

      }

    });

    return parameters;

  }

  // get a texture from the textureMap for use by a material.
  getTexture(textureMap, id) {

    // if the texture is a layered texture, just use the first layer and issue a warning
    if ('LayeredTexture' in fbxTree.Objects && id in fbxTree.Objects.LayeredTexture) {

      console.warn('THREE.FBXLoader: layered textures are not supported in three.js. Discarding all but first layer.');
      id = connections.get(id).children[0].ID;

    }

    return textureMap.get(id);

  }

  // Parse nodes in FBXTree.Objects.Deformer
  // Deformer node can contain skinning or Vertex Cache animation data, however only skinning is supported here
  // Generates map of Skeleton-like objects for use later when generating and binding skeletons.
  parseDeformers() {

    const skeletons = {};
    const morphTargets = {};

    if ('Deformer' in fbxTree.Objects) {

      const DeformerNodes = fbxTree.Objects.Deformer;

      for (const nodeID in DeformerNodes) {

        const deformerNode = DeformerNodes[nodeID];

        const relationships = connections.get(parseInt(nodeID));

        if (deformerNode.attrType === 'Skin') {

          const skeleton = this.parseSkeleton(relationships, DeformerNodes);
          skeleton.ID = nodeID;

          if (relationships.parents.length > 1) console.warn('THREE.FBXLoader: skeleton attached to more than one geometry is not supported.');
          skeleton.geometryID = relationships.parents[0].ID;

          skeletons[nodeID] = skeleton;

        } else if (deformerNode.attrType === 'BlendShape') {

          const morphTarget = {
            id: nodeID,
          };

          morphTarget.rawTargets = this.parseMorphTargets(relationships, DeformerNodes);
          morphTarget.id = nodeID;

          if (relationships.parents.length > 1) console.warn('THREE.FBXLoader: morph target attached to more than one geometry is not supported.');

          morphTargets[nodeID] = morphTarget;

        }

      }

    }

    return {

      skeletons: skeletons,
      morphTargets: morphTargets,

    };

  }

  // Parse single nodes in FBXTree.Objects.Deformer
  // The top level skeleton node has type 'Skin' and sub nodes have type 'Cluster'
  // Each skin node represents a skeleton and each cluster node represents a bone
  parseSkeleton(relationships, deformerNodes) {

    const rawBones = [];

    relationships.children.forEach(function (child) {

      const boneNode = deformerNodes[child.ID];

      if (boneNode.attrType !== 'Cluster') return;

      const rawBone = {

        ID: child.ID,
        indices: [],
        weights: [],
        transformLink: new Matrix4().fromArray(boneNode.TransformLink.a),
        // transform: new Matrix4().fromArray( boneNode.Transform.a ),
        // linkMode: boneNode.Mode,

      };

      if ('Indexes' in boneNode) {

        rawBone.indices = boneNode.Indexes.a;
        rawBone.weights = boneNode.Weights.a;

      }

      rawBones.push(rawBone);

    });

    return {

      rawBones: rawBones,
      bones: []

    };

  }

  // The top level morph deformer node has type "BlendShape" and sub nodes have type "BlendShapeChannel"
  parseMorphTargets(relationships, deformerNodes) {

    const rawMorphTargets = [];

    for (let i = 0; i < relationships.children.length; i++) {

      const child = relationships.children[i];

      const morphTargetNode = deformerNodes[child.ID];

      const rawMorphTarget = {

        name: morphTargetNode.attrName,
        initialWeight: morphTargetNode.DeformPercent,
        id: morphTargetNode.id,
        fullWeights: morphTargetNode.FullWeights.a

      };

      if (morphTargetNode.attrType !== 'BlendShapeChannel') return;

      rawMorphTarget.geoID = connections.get(parseInt(child.ID)).children.filter(function (child) {

        return child.relationship === undefined;

      })[0].ID;

      rawMorphTargets.push(rawMorphTarget);

    }

    return rawMorphTargets;

  }

  // create the main Group() to be returned by the loader
  parseScene(deformers, geometryMap, materialMap) {

    sceneGraph = new Group();

    const modelMap = this.parseModels(deformers.skeletons, geometryMap, materialMap);

    const modelNodes = fbxTree.Objects.Model;

    const scope = this;
    modelMap.forEach(function (model) {

      const modelNode = modelNodes[model.ID];
      scope.setLookAtProperties(model, modelNode);

      const parentConnections = connections.get(model.ID).parents;

      parentConnections.forEach(function (connection) {

        const parent = modelMap.get(connection.ID);
        if (parent !== undefined) parent.add(model);

      });

      if (model.parent === null) {

        sceneGraph.add(model);

      }


    });

    this.bindSkeleton(deformers.skeletons, geometryMap, modelMap);

    this.createAmbientLight();

    sceneGraph.traverse(function (node) {

      if (node.userData.transformData) {

        if (node.parent) {

          node.userData.transformData.parentMatrix = node.parent.matrix;
          node.userData.transformData.parentMatrixWorld = node.parent.matrixWorld;

        }

        const transform = generateTransform(node.userData.transformData);

        node.applyMatrix4(transform);
        node.updateWorldMatrix();

      }

    });

    const animations = new AnimationParser().parse();

    // if all the models where already combined in a single group, just return that
    if (sceneGraph.children.length === 1 && sceneGraph.children[0].isGroup) {

      sceneGraph.children[0].animations = animations;
      sceneGraph = sceneGraph.children[0];

    }

    sceneGraph.animations = animations;

  }

  // parse nodes in FBXTree.Objects.Model
  parseModels(skeletons, geometryMap, materialMap) {

    const modelMap = new Map();
    const modelNodes = fbxTree.Objects.Model;

    for (const nodeID in modelNodes) {

      const id = parseInt(nodeID);
      const node = modelNodes[nodeID];
      const relationships = connections.get(id);

      let model = this.buildSkeleton(relationships, skeletons, id, node.attrName);

      if (!model) {

        switch (node.attrType) {

          case 'Camera':
            model = this.createCamera(relationships);
            break;
          case 'Light':
            model = this.createLight(relationships);
            break;
          case 'Mesh':
            model = this.createMesh(relationships, geometryMap, materialMap);
            break;
          case 'NurbsCurve':
            model = this.createCurve(relationships, geometryMap);
            break;
          case 'LimbNode':
          case 'Root':
            model = new Bone();
            break;
          case 'Null':
          default:
            model = new Group();
            break;

        }

        model.name = node.attrName ? PropertyBinding.sanitizeNodeName(node.attrName) : '';

        model.ID = id;

      }

      this.getTransformData(model, node);
      modelMap.set(id, model);

    }

    return modelMap;

  }

  buildSkeleton(relationships, skeletons, id, name) {

    let bone = null;

    relationships.parents.forEach(function (parent) {

      for (const ID in skeletons) {

        const skeleton = skeletons[ID];

        skeleton.rawBones.forEach(function (rawBone, i) {

          if (rawBone.ID === parent.ID) {

            const subBone = bone;
            bone = new Bone();

            bone.matrixWorld.copy(rawBone.transformLink);

            // set name and id here - otherwise in cases where "subBone" is created it will not have a name / id

            bone.name = name ? PropertyBinding.sanitizeNodeName(name) : '';
            bone.ID = id;

            skeleton.bones[i] = bone;

            // In cases where a bone is shared between multiple meshes
            // duplicate the bone here and and it as a child of the first bone
            if (subBone !== null) {

              bone.add(subBone);

            }

          }

        });

      }

    });

    return bone;

  }

  // create a PerspectiveCamera or OrthographicCamera
  createCamera(relationships) {

    let model;
    let cameraAttribute;

    relationships.children.forEach(function (child) {

      const attr = fbxTree.Objects.NodeAttribute[child.ID];

      if (attr !== undefined) {

        cameraAttribute = attr;

      }

    });

    if (cameraAttribute === undefined) {

      model = new Object3D();

    } else {

      let type = 0;
      if (cameraAttribute.CameraProjectionType !== undefined && cameraAttribute.CameraProjectionType.value === 1) {

        type = 1;

      }

      let nearClippingPlane = 1;
      if (cameraAttribute.NearPlane !== undefined) {

        nearClippingPlane = cameraAttribute.NearPlane.value / 1000;

      }

      let farClippingPlane = 1000;
      if (cameraAttribute.FarPlane !== undefined) {

        farClippingPlane = cameraAttribute.FarPlane.value / 1000;

      }


      let width = window.innerWidth;
      let height = window.innerHeight;

      if (cameraAttribute.AspectWidth !== undefined && cameraAttribute.AspectHeight !== undefined) {

        width = cameraAttribute.AspectWidth.value;
        height = cameraAttribute.AspectHeight.value;

      }

      const aspect = width / height;

      let fov = 45;
      if (cameraAttribute.FieldOfView !== undefined) {

        fov = cameraAttribute.FieldOfView.value;

      }

      const focalLength = cameraAttribute.FocalLength ? cameraAttribute.FocalLength.value : null;

      switch (type) {

        case 0: // Perspective
          model = new PerspectiveCamera(fov, aspect, nearClippingPlane, farClippingPlane);
          if (focalLength !== null) model.setFocalLength(focalLength);
          break;

        case 1: // Orthographic
          model = new OrthographicCamera(-width / 2, width / 2, height / 2, -height / 2, nearClippingPlane, farClippingPlane);
          break;

        default:
          console.warn('THREE.FBXLoader: Unknown camera type ' + type + '.');
          model = new Object3D();
          break;

      }

    }

    return model;

  }

  // Create a DirectionalLight, PointLight or SpotLight
  createLight(relationships) {

    let model;
    let lightAttribute;

    relationships.children.forEach(function (child) {

      const attr = fbxTree.Objects.NodeAttribute[child.ID];

      if (attr !== undefined) {

        lightAttribute = attr;

      }

    });

    if (lightAttribute === undefined) {

      model = new Object3D();

    } else {

      let type;

      // LightType can be undefined for Point lights
      if (lightAttribute.LightType === undefined) {

        type = 0;

      } else {

        type = lightAttribute.LightType.value;

      }

      let color = 0xffffff;

      if (lightAttribute.Color !== undefined) {

        color = new Color().fromArray(lightAttribute.Color.value);

      }

      let intensity = (lightAttribute.Intensity === undefined) ? 1 : lightAttribute.Intensity.value / 100;

      // light disabled
      if (lightAttribute.CastLightOnObject !== undefined && lightAttribute.CastLightOnObject.value === 0) {

        intensity = 0;

      }

      let distance = 0;
      if (lightAttribute.FarAttenuationEnd !== undefined) {

        if (lightAttribute.EnableFarAttenuation !== undefined && lightAttribute.EnableFarAttenuation.value === 0) {

          distance = 0;

        } else {

          distance = lightAttribute.FarAttenuationEnd.value;

        }

      }

      // TODO: could this be calculated linearly from FarAttenuationStart to FarAttenuationEnd?
      const decay = 1;

      switch (type) {

        case 0: // Point
          model = new PointLight(color, intensity, distance, decay);
          break;

        case 1: // Directional
          model = new DirectionalLight(color, intensity);
          break;

        case 2: // Spot
          let angle = Math.PI / 3;

          if (lightAttribute.InnerAngle !== undefined) {

            angle = MathUtils.degToRad(lightAttribute.InnerAngle.value);

          }

          let penumbra = 0;
          if (lightAttribute.OuterAngle !== undefined) {

            // TODO: this is not correct - FBX calculates outer and inner angle in degrees
            // with OuterAngle > InnerAngle && OuterAngle <= Math.PI
            // while three.js uses a penumbra between (0, 1) to attenuate the inner angle
            penumbra = MathUtils.degToRad(lightAttribute.OuterAngle.value);
            penumbra = Math.max(penumbra, 1);

          }

          model = new SpotLight(color, intensity, distance, angle, penumbra, decay);
          break;

        default:
          console.warn('THREE.FBXLoader: Unknown light type ' + lightAttribute.LightType.value + ', defaulting to a PointLight.');
          model = new PointLight(color, intensity);
          break;

      }

      if (lightAttribute.CastShadows !== undefined && lightAttribute.CastShadows.value === 1) {

        model.castShadow = true;

      }

    }

    return model;

  }

  createMesh(relationships, geometryMap, materialMap) {

    let model;
    let geometry = null;
    let material = null;
    const materials = [];

    // get geometry and materials(s) from connections
    relationships.children.forEach(function (child) {

      if (geometryMap.has(child.ID)) {

        geometry = geometryMap.get(child.ID);

      }

      if (materialMap.has(child.ID)) {

        materials.push(materialMap.get(child.ID));

      }

    });

    if (materials.length > 1) {

      material = materials;

    } else if (materials.length > 0) {

      material = materials[0];

    } else {

      material = new MeshPhongMaterial({color: 0xcccccc});
      materials.push(material);

    }

    if ('color' in geometry.attributes) {

      materials.forEach(function (material) {

        material.vertexColors = true;

      });

    }

    if (geometry.FBX_Deformer) {

      model = new SkinnedMesh(geometry, material);
      model.normalizeSkinWeights();

    } else {

      model = new Mesh(geometry, material);

    }

    return model;

  }

  createCurve(relationships, geometryMap) {

    const geometry = relationships.children.reduce(function (geo, child) {

      if (geometryMap.has(child.ID)) geo = geometryMap.get(child.ID);

      return geo;

    }, null);

    // FBX does not list materials for Nurbs lines, so we'll just put our own in here.
    const material = new LineBasicMaterial({color: 0x3300ff, linewidth: 1});
    return new Line(geometry, material);

  }

  // parse the model node for transform data
  getTransformData(model, modelNode) {

    const transformData = {};

    if ('InheritType' in modelNode) transformData.inheritType = parseInt(modelNode.InheritType.value);

    if ('RotationOrder' in modelNode) transformData.eulerOrder = getEulerOrder(modelNode.RotationOrder.value);
    else transformData.eulerOrder = 'ZYX';

    if ('Lcl_Translation' in modelNode) transformData.translation = modelNode.Lcl_Translation.value;

    if ('PreRotation' in modelNode) transformData.preRotation = modelNode.PreRotation.value;
    if ('Lcl_Rotation' in modelNode) transformData.rotation = modelNode.Lcl_Rotation.value;
    if ('PostRotation' in modelNode) transformData.postRotation = modelNode.PostRotation.value;

    if ('Lcl_Scaling' in modelNode) transformData.scale = modelNode.Lcl_Scaling.value;

    if ('ScalingOffset' in modelNode) transformData.scalingOffset = modelNode.ScalingOffset.value;
    if ('ScalingPivot' in modelNode) transformData.scalingPivot = modelNode.ScalingPivot.value;

    if ('RotationOffset' in modelNode) transformData.rotationOffset = modelNode.RotationOffset.value;
    if ('RotationPivot' in modelNode) transformData.rotationPivot = modelNode.RotationPivot.value;

    model.userData.transformData = transformData;

  }

  setLookAtProperties(model, modelNode) {

    if ('LookAtProperty' in modelNode) {

      const children = connections.get(model.ID).children;

      children.forEach(function (child) {

        if (child.relationship === 'LookAtProperty') {

          const lookAtTarget = fbxTree.Objects.Model[child.ID];

          if ('Lcl_Translation' in lookAtTarget) {

            const pos = lookAtTarget.Lcl_Translation.value;

            // DirectionalLight, SpotLight
            if (model.target !== undefined) {

              model.target.position.fromArray(pos);
              sceneGraph.add(model.target);

            } else { // Cameras and other Object3Ds

              model.lookAt(new Vector3().fromArray(pos));

            }

          }

        }

      });

    }

  }

  bindSkeleton(skeletons, geometryMap, modelMap) {

    const bindMatrices = this.parsePoseNodes();

    for (const ID in skeletons) {

      const skeleton = skeletons[ID];

      const parents = connections.get(parseInt(skeleton.ID)).parents;

      parents.forEach(function (parent) {

        if (geometryMap.has(parent.ID)) {

          const geoID = parent.ID;
          const geoRelationships = connections.get(geoID);

          geoRelationships.parents.forEach(function (geoConnParent) {

            if (modelMap.has(geoConnParent.ID)) {

              const model = modelMap.get(geoConnParent.ID);

              model.bind(new Skeleton(skeleton.bones), bindMatrices[geoConnParent.ID]);

            }

          });

        }

      });

    }

  }

  parsePoseNodes() {

    const bindMatrices = {};

    if ('Pose' in fbxTree.Objects) {

      const BindPoseNode = fbxTree.Objects.Pose;

      for (const nodeID in BindPoseNode) {

        if (BindPoseNode[nodeID].attrType === 'BindPose' && BindPoseNode[nodeID].NbPoseNodes > 0) {

          const poseNodes = BindPoseNode[nodeID].PoseNode;

          if (Array.isArray(poseNodes)) {

            poseNodes.forEach(function (poseNode) {

              bindMatrices[poseNode.Node] = new Matrix4().fromArray(poseNode.Matrix.a);

            });

          } else {

            bindMatrices[poseNodes.Node] = new Matrix4().fromArray(poseNodes.Matrix.a);

          }

        }

      }

    }

    return bindMatrices;

  }

  // Parse ambient color in FBXTree.GlobalSettings - if it's not set to black (default), create an ambient light
  createAmbientLight() {

    if ('GlobalSettings' in fbxTree && 'AmbientColor' in fbxTree.GlobalSettings) {

      const ambientColor = fbxTree.GlobalSettings.AmbientColor.value;
      const r = ambientColor[0];
      const g = ambientColor[1];
      const b = ambientColor[2];

      if (r !== 0 || g !== 0 || b !== 0) {

        const color = new Color(r, g, b);
        sceneGraph.add(new AmbientLight(color, 1));

      }

    }

  }

}

// parse Geometry data from FBXTree and return map of BufferGeometries
class GeometryParser {

  // Parse nodes in FBXTree.Objects.Geometry
  parse(deformers) {

    const geometryMap = new Map();

    if ('Geometry' in fbxTree.Objects) {

      const geoNodes = fbxTree.Objects.Geometry;

      for (const nodeID in geoNodes) {

        const relationships = connections.get(parseInt(nodeID));
        const geo = this.parseGeometry(relationships, geoNodes[nodeID], deformers);

        geometryMap.set(parseInt(nodeID), geo);

      }

    }

    return geometryMap;

  }

  // Parse single node in FBXTree.Objects.Geometry
  parseGeometry(relationships, geoNode, deformers) {

    switch (geoNode.attrType) {

      case 'Mesh':
        return this.parseMeshGeometry(relationships, geoNode, deformers);
        break;

      case 'NurbsCurve':
        return this.parseNurbsGeometry(geoNode);
        break;

    }

  }

  // Parse single node mesh geometry in FBXTree.Objects.Geometry
  parseMeshGeometry(relationships, geoNode, deformers) {

    const skeletons = deformers.skeletons;
    const morphTargets = [];

    const modelNodes = relationships.parents.map(function (parent) {

      return fbxTree.Objects.Model[parent.ID];

    });

    // don't create geometry if it is not associated with any models
    if (modelNodes.length === 0) return;

    const skeleton = relationships.children.reduce(function (skeleton, child) {

      if (skeletons[child.ID] !== undefined) skeleton = skeletons[child.ID];

      return skeleton;

    }, null);

    relationships.children.forEach(function (child) {

      if (deformers.morphTargets[child.ID] !== undefined) {

        morphTargets.push(deformers.morphTargets[child.ID]);

      }

    });

    // Assume one model and get the preRotation from that
    // if there is more than one model associated with the geometry this may cause problems
    const modelNode = modelNodes[0];

    const transformData = {};

    if ('RotationOrder' in modelNode) transformData.eulerOrder = getEulerOrder(modelNode.RotationOrder.value);
    if ('InheritType' in modelNode) transformData.inheritType = parseInt(modelNode.InheritType.value);

    if ('GeometricTranslation' in modelNode) transformData.translation = modelNode.GeometricTranslation.value;
    if ('GeometricRotation' in modelNode) transformData.rotation = modelNode.GeometricRotation.value;
    if ('GeometricScaling' in modelNode) transformData.scale = modelNode.GeometricScaling.value;

    const transform = generateTransform(transformData);

    return this.genGeometry(geoNode, skeleton, morphTargets, transform);

  }

  // Generate a BufferGeometry from a node in FBXTree.Objects.Geometry
  genGeometry(geoNode, skeleton, morphTargets, preTransform) {

    const geo = new BufferGeometry();
    if (geoNode.attrName) geo.name = geoNode.attrName;

    const geoInfo = this.parseGeoNode(geoNode, skeleton);
    const buffers = this.genBuffers(geoInfo);

    const positionAttribute = new Float32BufferAttribute(buffers.vertex, 3);

    positionAttribute.applyMatrix4(preTransform);

    geo.setAttribute('position', positionAttribute);

    if (buffers.colors.length > 0) {

      geo.setAttribute('color', new Float32BufferAttribute(buffers.colors, 3));

    }

    if (skeleton) {

      geo.setAttribute('skinIndex', new Uint16BufferAttribute(buffers.weightsIndices, 4));

      geo.setAttribute('skinWeight', new Float32BufferAttribute(buffers.vertexWeights, 4));

      // used later to bind the skeleton to the model
      geo.FBX_Deformer = skeleton;

    }

    if (buffers.normal.length > 0) {

      const normalMatrix = new Matrix3().getNormalMatrix(preTransform);

      const normalAttribute = new Float32BufferAttribute(buffers.normal, 3);
      normalAttribute.applyNormalMatrix(normalMatrix);

      geo.setAttribute('normal', normalAttribute);

    }

    buffers.uvs.forEach(function (uvBuffer, i) {

      // subsequent uv buffers are called 'uv1', 'uv2', ...
      let name = 'uv' + (i + 1).toString();

      // the first uv buffer is just called 'uv'
      if (i === 0) {

        name = 'uv';

      }

      geo.setAttribute(name, new Float32BufferAttribute(buffers.uvs[i], 2));

    });

    if (geoInfo.material && geoInfo.material.mappingType !== 'AllSame') {

      // Convert the material indices of each vertex into rendering groups on the geometry.
      let prevMaterialIndex = buffers.materialIndex[0];
      let startIndex = 0;

      buffers.materialIndex.forEach(function (currentIndex, i) {

        if (currentIndex !== prevMaterialIndex) {

          geo.addGroup(startIndex, i - startIndex, prevMaterialIndex);

          prevMaterialIndex = currentIndex;
          startIndex = i;

        }

      });

      // the loop above doesn't add the last group, do that here.
      if (geo.groups.length > 0) {

        const lastGroup = geo.groups[geo.groups.length - 1];
        const lastIndex = lastGroup.start + lastGroup.count;

        if (lastIndex !== buffers.materialIndex.length) {

          geo.addGroup(lastIndex, buffers.materialIndex.length - lastIndex, prevMaterialIndex);

        }

      }

      // case where there are multiple materials but the whole geometry is only
      // using one of them
      if (geo.groups.length === 0) {

        geo.addGroup(0, buffers.materialIndex.length, buffers.materialIndex[0]);

      }

    }

    this.addMorphTargets(geo, geoNode, morphTargets, preTransform);

    return geo;

  }

  parseGeoNode(geoNode, skeleton) {

    const geoInfo = {};

    geoInfo.vertexPositions = (geoNode.Vertices !== undefined) ? geoNode.Vertices.a : [];
    geoInfo.vertexIndices = (geoNode.PolygonVertexIndex !== undefined) ? geoNode.PolygonVertexIndex.a : [];

    if (geoNode.LayerElementColor) {

      geoInfo.color = this.parseVertexColors(geoNode.LayerElementColor[0]);

    }

    if (geoNode.LayerElementMaterial) {

      geoInfo.material = this.parseMaterialIndices(geoNode.LayerElementMaterial[0]);

    }

    if (geoNode.LayerElementNormal) {

      geoInfo.normal = this.parseNormals(geoNode.LayerElementNormal[0]);

    }

    if (geoNode.LayerElementUV) {

      geoInfo.uv = [];

      let i = 0;
      while (geoNode.LayerElementUV[i]) {

        if (geoNode.LayerElementUV[i].UV) {

          geoInfo.uv.push(this.parseUVs(geoNode.LayerElementUV[i]));

        }

        i++;

      }

    }

    geoInfo.weightTable = {};

    if (skeleton !== null) {

      geoInfo.skeleton = skeleton;

      skeleton.rawBones.forEach(function (rawBone, i) {

        // loop over the bone's vertex indices and weights
        rawBone.indices.forEach(function (index, j) {

          if (geoInfo.weightTable[index] === undefined) geoInfo.weightTable[index] = [];

          geoInfo.weightTable[index].push({

            id: i,
            weight: rawBone.weights[j],

          });

        });

      });

    }

    return geoInfo;

  }

  genBuffers(geoInfo) {

    const buffers = {
      vertex: [],
      normal: [],
      colors: [],
      uvs: [],
      materialIndex: [],
      vertexWeights: [],
      weightsIndices: [],
    };

    let polygonIndex = 0;
    let faceLength = 0;
    let displayedWeightsWarning = false;

    // these will hold data for a single face
    let facePositionIndexes = [];
    let faceNormals = [];
    let faceColors = [];
    let faceUVs = [];
    let faceWeights = [];
    let faceWeightIndices = [];

    const scope = this;
    geoInfo.vertexIndices.forEach(function (vertexIndex, polygonVertexIndex) {

      let materialIndex;
      let endOfFace = false;

      // Face index and vertex index arrays are combined in a single array
      // A cube with quad faces looks like this:
      // PolygonVertexIndex: *24 {
      //  a: 0, 1, 3, -3, 2, 3, 5, -5, 4, 5, 7, -7, 6, 7, 1, -1, 1, 7, 5, -4, 6, 0, 2, -5
      //  }
      // Negative numbers mark the end of a face - first face here is 0, 1, 3, -3
      // to find index of last vertex bit shift the index: ^ - 1
      if (vertexIndex < 0) {

        vertexIndex = vertexIndex ^ -1; // equivalent to ( x * -1 ) - 1
        endOfFace = true;

      }

      let weightIndices = [];
      let weights = [];

      facePositionIndexes.push(vertexIndex * 3, vertexIndex * 3 + 1, vertexIndex * 3 + 2);

      if (geoInfo.color) {

        const data = getData(polygonVertexIndex, polygonIndex, vertexIndex, geoInfo.color);

        faceColors.push(data[0], data[1], data[2]);

      }

      if (geoInfo.skeleton) {

        if (geoInfo.weightTable[vertexIndex] !== undefined) {

          geoInfo.weightTable[vertexIndex].forEach(function (wt) {

            weights.push(wt.weight);
            weightIndices.push(wt.id);

          });


        }

        if (weights.length > 4) {

          if (!displayedWeightsWarning) {

            console.warn('THREE.FBXLoader: Vertex has more than 4 skinning weights assigned to vertex. Deleting additional weights.');
            displayedWeightsWarning = true;

          }

          const wIndex = [0, 0, 0, 0];
          const Weight = [0, 0, 0, 0];

          weights.forEach(function (weight, weightIndex) {

            let currentWeight = weight;
            let currentIndex = weightIndices[weightIndex];

            Weight.forEach(function (comparedWeight, comparedWeightIndex, comparedWeightArray) {

              if (currentWeight > comparedWeight) {

                comparedWeightArray[comparedWeightIndex] = currentWeight;
                currentWeight = comparedWeight;

                const tmp = wIndex[comparedWeightIndex];
                wIndex[comparedWeightIndex] = currentIndex;
                currentIndex = tmp;

              }

            });

          });

          weightIndices = wIndex;
          weights = Weight;

        }

        // if the weight array is shorter than 4 pad with 0s
        while (weights.length < 4) {

          weights.push(0);
          weightIndices.push(0);

        }

        for (let i = 0; i < 4; ++i) {

          faceWeights.push(weights[i]);
          faceWeightIndices.push(weightIndices[i]);

        }

      }

      if (geoInfo.normal) {

        const data = getData(polygonVertexIndex, polygonIndex, vertexIndex, geoInfo.normal);

        faceNormals.push(data[0], data[1], data[2]);

      }

      if (geoInfo.material && geoInfo.material.mappingType !== 'AllSame') {

        materialIndex = getData(polygonVertexIndex, polygonIndex, vertexIndex, geoInfo.material)[0];

      }

      if (geoInfo.uv) {

        geoInfo.uv.forEach(function (uv, i) {

          const data = getData(polygonVertexIndex, polygonIndex, vertexIndex, uv);

          if (faceUVs[i] === undefined) {

            faceUVs[i] = [];

          }

          faceUVs[i].push(data[0]);
          faceUVs[i].push(data[1]);

        });

      }

      faceLength++;

      if (endOfFace) {

        scope.genFace(buffers, geoInfo, facePositionIndexes, materialIndex, faceNormals, faceColors, faceUVs, faceWeights, faceWeightIndices, faceLength);

        polygonIndex++;
        faceLength = 0;

        // reset arrays for the next face
        facePositionIndexes = [];
        faceNormals = [];
        faceColors = [];
        faceUVs = [];
        faceWeights = [];
        faceWeightIndices = [];

      }

    });

    return buffers;

  }

  // Generate data for a single face in a geometry. If the face is a quad then split it into 2 tris
  genFace(buffers, geoInfo, facePositionIndexes, materialIndex, faceNormals, faceColors, faceUVs, faceWeights, faceWeightIndices, faceLength) {

    for (let i = 2; i < faceLength; i++) {

      buffers.vertex.push(geoInfo.vertexPositions[facePositionIndexes[0]]);
      buffers.vertex.push(geoInfo.vertexPositions[facePositionIndexes[1]]);
      buffers.vertex.push(geoInfo.vertexPositions[facePositionIndexes[2]]);

      buffers.vertex.push(geoInfo.vertexPositions[facePositionIndexes[(i - 1) * 3]]);
      buffers.vertex.push(geoInfo.vertexPositions[facePositionIndexes[(i - 1) * 3 + 1]]);
      buffers.vertex.push(geoInfo.vertexPositions[facePositionIndexes[(i - 1) * 3 + 2]]);

      buffers.vertex.push(geoInfo.vertexPositions[facePositionIndexes[i * 3]]);
      buffers.vertex.push(geoInfo.vertexPositions[facePositionIndexes[i * 3 + 1]]);
      buffers.vertex.push(geoInfo.vertexPositions[facePositionIndexes[i * 3 + 2]]);

      if (geoInfo.skeleton) {

        buffers.vertexWeights.push(faceWeights[0]);
        buffers.vertexWeights.push(faceWeights[1]);
        buffers.vertexWeights.push(faceWeights[2]);
        buffers.vertexWeights.push(faceWeights[3]);

        buffers.vertexWeights.push(faceWeights[(i - 1) * 4]);
        buffers.vertexWeights.push(faceWeights[(i - 1) * 4 + 1]);
        buffers.vertexWeights.push(faceWeights[(i - 1) * 4 + 2]);
        buffers.vertexWeights.push(faceWeights[(i - 1) * 4 + 3]);

        buffers.vertexWeights.push(faceWeights[i * 4]);
        buffers.vertexWeights.push(faceWeights[i * 4 + 1]);
        buffers.vertexWeights.push(faceWeights[i * 4 + 2]);
        buffers.vertexWeights.push(faceWeights[i * 4 + 3]);

        buffers.weightsIndices.push(faceWeightIndices[0]);
        buffers.weightsIndices.push(faceWeightIndices[1]);
        buffers.weightsIndices.push(faceWeightIndices[2]);
        buffers.weightsIndices.push(faceWeightIndices[3]);

        buffers.weightsIndices.push(faceWeightIndices[(i - 1) * 4]);
        buffers.weightsIndices.push(faceWeightIndices[(i - 1) * 4 + 1]);
        buffers.weightsIndices.push(faceWeightIndices[(i - 1) * 4 + 2]);
        buffers.weightsIndices.push(faceWeightIndices[(i - 1) * 4 + 3]);

        buffers.weightsIndices.push(faceWeightIndices[i * 4]);
        buffers.weightsIndices.push(faceWeightIndices[i * 4 + 1]);
        buffers.weightsIndices.push(faceWeightIndices[i * 4 + 2]);
        buffers.weightsIndices.push(faceWeightIndices[i * 4 + 3]);

      }

      if (geoInfo.color) {

        buffers.colors.push(faceColors[0]);
        buffers.colors.push(faceColors[1]);
        buffers.colors.push(faceColors[2]);

        buffers.colors.push(faceColors[(i - 1) * 3]);
        buffers.colors.push(faceColors[(i - 1) * 3 + 1]);
        buffers.colors.push(faceColors[(i - 1) * 3 + 2]);

        buffers.colors.push(faceColors[i * 3]);
        buffers.colors.push(faceColors[i * 3 + 1]);
        buffers.colors.push(faceColors[i * 3 + 2]);

      }

      if (geoInfo.material && geoInfo.material.mappingType !== 'AllSame') {

        buffers.materialIndex.push(materialIndex);
        buffers.materialIndex.push(materialIndex);
        buffers.materialIndex.push(materialIndex);

      }

      if (geoInfo.normal) {

        buffers.normal.push(faceNormals[0]);
        buffers.normal.push(faceNormals[1]);
        buffers.normal.push(faceNormals[2]);

        buffers.normal.push(faceNormals[(i - 1) * 3]);
        buffers.normal.push(faceNormals[(i - 1) * 3 + 1]);
        buffers.normal.push(faceNormals[(i - 1) * 3 + 2]);

        buffers.normal.push(faceNormals[i * 3]);
        buffers.normal.push(faceNormals[i * 3 + 1]);
        buffers.normal.push(faceNormals[i * 3 + 2]);

      }

      if (geoInfo.uv) {

        geoInfo.uv.forEach(function (uv, j) {

          if (buffers.uvs[j] === undefined) buffers.uvs[j] = [];

          buffers.uvs[j].push(faceUVs[j][0]);
          buffers.uvs[j].push(faceUVs[j][1]);

          buffers.uvs[j].push(faceUVs[j][(i - 1) * 2]);
          buffers.uvs[j].push(faceUVs[j][(i - 1) * 2 + 1]);

          buffers.uvs[j].push(faceUVs[j][i * 2]);
          buffers.uvs[j].push(faceUVs[j][i * 2 + 1]);

        });

      }

    }

  }

  addMorphTargets(parentGeo, parentGeoNode, morphTargets, preTransform) {

    if (morphTargets.length === 0) return;

    parentGeo.morphTargetsRelative = true;

    parentGeo.morphAttributes.position = [];
    // parentGeo.morphAttributes.normal = []; // not implemented

    const scope = this;
    morphTargets.forEach(function (morphTarget) {

      morphTarget.rawTargets.forEach(function (rawTarget) {

        const morphGeoNode = fbxTree.Objects.Geometry[rawTarget.geoID];

        if (morphGeoNode !== undefined) {

          scope.genMorphGeometry(parentGeo, parentGeoNode, morphGeoNode, preTransform, rawTarget.name);

        }

      });

    });

  }

  // a morph geometry node is similar to a standard  node, and the node is also contained
  // in FBXTree.Objects.Geometry, however it can only have attributes for position, normal
  // and a special attribute Index defining which vertices of the original geometry are affected
  // Normal and position attributes only have data for the vertices that are affected by the morph
  genMorphGeometry(parentGeo, parentGeoNode, morphGeoNode, preTransform, name) {

    const vertexIndices = (parentGeoNode.PolygonVertexIndex !== undefined) ? parentGeoNode.PolygonVertexIndex.a : [];

    const morphPositionsSparse = (morphGeoNode.Vertices !== undefined) ? morphGeoNode.Vertices.a : [];
    const indices = (morphGeoNode.Indexes !== undefined) ? morphGeoNode.Indexes.a : [];

    const length = parentGeo.attributes.position.count * 3;
    const morphPositions = new Float32Array(length);

    for (let i = 0; i < indices.length; i++) {

      const morphIndex = indices[i] * 3;

      morphPositions[morphIndex] = morphPositionsSparse[i * 3];
      morphPositions[morphIndex + 1] = morphPositionsSparse[i * 3 + 1];
      morphPositions[morphIndex + 2] = morphPositionsSparse[i * 3 + 2];

    }

    // TODO: add morph normal support
    const morphGeoInfo = {
      vertexIndices: vertexIndices,
      vertexPositions: morphPositions,

    };

    const morphBuffers = this.genBuffers(morphGeoInfo);

    const positionAttribute = new Float32BufferAttribute(morphBuffers.vertex, 3);
    positionAttribute.name = name || morphGeoNode.attrName;

    positionAttribute.applyMatrix4(preTransform);

    parentGeo.morphAttributes.position.push(positionAttribute);

  }

  // Parse normal from FBXTree.Objects.Geometry.LayerElementNormal if it exists
  parseNormals(NormalNode) {

    const mappingType = NormalNode.MappingInformationType;
    const referenceType = NormalNode.ReferenceInformationType;
    const buffer = NormalNode.Normals.a;
    let indexBuffer = [];
    if (referenceType === 'IndexToDirect') {

      if ('NormalIndex' in NormalNode) {

        indexBuffer = NormalNode.NormalIndex.a;

      } else if ('NormalsIndex' in NormalNode) {

        indexBuffer = NormalNode.NormalsIndex.a;

      }

    }

    return {
      dataSize: 3,
      buffer: buffer,
      indices: indexBuffer,
      mappingType: mappingType,
      referenceType: referenceType
    };

  }

  // Parse UVs from FBXTree.Objects.Geometry.LayerElementUV if it exists
  parseUVs(UVNode) {

    const mappingType = UVNode.MappingInformationType;
    const referenceType = UVNode.ReferenceInformationType;
    const buffer = UVNode.UV.a;
    let indexBuffer = [];
    if (referenceType === 'IndexToDirect') {

      indexBuffer = UVNode.UVIndex.a;

    }

    return {
      dataSize: 2,
      buffer: buffer,
      indices: indexBuffer,
      mappingType: mappingType,
      referenceType: referenceType
    };

  }

  // Parse Vertex Colors from FBXTree.Objects.Geometry.LayerElementColor if it exists
  parseVertexColors(ColorNode) {

    const mappingType = ColorNode.MappingInformationType;
    const referenceType = ColorNode.ReferenceInformationType;
    const buffer = ColorNode.Colors.a;
    let indexBuffer = [];
    if (referenceType === 'IndexToDirect') {

      indexBuffer = ColorNode.ColorIndex.a;

    }

    return {
      dataSize: 4,
      buffer: buffer,
      indices: indexBuffer,
      mappingType: mappingType,
      referenceType: referenceType
    };

  }

  // Parse mapping and material data in FBXTree.Objects.Geometry.LayerElementMaterial if it exists
  parseMaterialIndices(MaterialNode) {

    const mappingType = MaterialNode.MappingInformationType;
    const referenceType = MaterialNode.ReferenceInformationType;

    if (mappingType === 'NoMappingInformation') {

      return {
        dataSize: 1,
        buffer: [0],
        indices: [0],
        mappingType: 'AllSame',
        referenceType: referenceType
      };

    }

    const materialIndexBuffer = MaterialNode.Materials.a;

    // Since materials are stored as indices, there's a bit of a mismatch between FBX and what
    // we expect.So we create an intermediate buffer that points to the index in the buffer,
    // for conforming with the other functions we've written for other data.
    const materialIndices = [];

    for (let i = 0; i < materialIndexBuffer.length; ++i) {

      materialIndices.push(i);

    }

    return {
      dataSize: 1,
      buffer: materialIndexBuffer,
      indices: materialIndices,
      mappingType: mappingType,
      referenceType: referenceType
    };

  }

  // Generate a NurbGeometry from a node in FBXTree.Objects.Geometry
  parseNurbsGeometry(geoNode) {

    if (NURBSCurve === undefined) {

      console.error('THREE.FBXLoader: The loader relies on NURBSCurve for any nurbs present in the model. Nurbs will show up as empty geometry.');
      return new BufferGeometry();

    }

    const order = parseInt(geoNode.Order);

    if (isNaN(order)) {

      console.error('THREE.FBXLoader: Invalid Order %s given for geometry ID: %s', geoNode.Order, geoNode.id);
      return new BufferGeometry();

    }

    const degree = order - 1;

    const knots = geoNode.KnotVector.a;
    const controlPoints = [];
    const pointsValues = geoNode.Points.a;

    for (let i = 0, l = pointsValues.length; i < l; i += 4) {

      controlPoints.push(new Vector4().fromArray(pointsValues, i));

    }

    let startKnot, endKnot;

    if (geoNode.Form === 'Closed') {

      controlPoints.push(controlPoints[0]);

    } else if (geoNode.Form === 'Periodic') {

      startKnot = degree;
      endKnot = knots.length - 1 - startKnot;

      for (let i = 0; i < degree; ++i) {

        controlPoints.push(controlPoints[i]);

      }

    }

    const curve = new NURBSCurve(degree, knots, controlPoints, startKnot, endKnot);
    const points = curve.getPoints(controlPoints.length * 12);

    return new BufferGeometry().setFromPoints(points);

  }

}

// parse animation data from FBXTree
class AnimationParser {

  // take raw animation clips and turn them into three.js animation clips
  parse() {

    const animationClips = [];

    const rawClips = this.parseClips();

    if (rawClips !== undefined) {

      for (const key in rawClips) {

        const rawClip = rawClips[key];

        const clip = this.addClip(rawClip);

        animationClips.push(clip);

      }

    }

    return animationClips;

  }

  parseClips() {

    // since the actual transformation data is stored in FBXTree.Objects.AnimationCurve,
    // if this is undefined we can safely assume there are no animations
    if (fbxTree.Objects.AnimationCurve === undefined) return undefined;

    const curveNodesMap = this.parseAnimationCurveNodes();

    this.parseAnimationCurves(curveNodesMap);

    const layersMap = this.parseAnimationLayers(curveNodesMap);
    const rawClips = this.parseAnimStacks(layersMap);

    return rawClips;

  }

  // parse nodes in FBXTree.Objects.AnimationCurveNode
  // each AnimationCurveNode holds data for an animation transform for a model (e.g. left arm rotation )
  // and is referenced by an AnimationLayer
  parseAnimationCurveNodes() {

    const rawCurveNodes = fbxTree.Objects.AnimationCurveNode;

    const curveNodesMap = new Map();

    for (const nodeID in rawCurveNodes) {

      const rawCurveNode = rawCurveNodes[nodeID];

      if (rawCurveNode.attrName.match(/S|R|T|DeformPercent/) !== null) {

        const curveNode = {

          id: rawCurveNode.id,
          attr: rawCurveNode.attrName,
          curves: {},

        };

        curveNodesMap.set(curveNode.id, curveNode);

      }

    }

    return curveNodesMap;

  }

  // parse nodes in FBXTree.Objects.AnimationCurve and connect them up to
  // previously parsed AnimationCurveNodes. Each AnimationCurve holds data for a single animated
  // axis ( e.g. times and values of x rotation)
  parseAnimationCurves(curveNodesMap) {

    const rawCurves = fbxTree.Objects.AnimationCurve;

    // TODO: Many values are identical up to roundoff error, but won't be optimised
    // e.g. position times: [0, 0.4, 0. 8]
    // position values: [7.23538335023477e-7, 93.67518615722656, -0.9982695579528809, 7.23538335023477e-7, 93.67518615722656, -0.9982695579528809, 7.235384487103147e-7, 93.67520904541016, -0.9982695579528809]
    // clearly, this should be optimised to
    // times: [0], positions [7.23538335023477e-7, 93.67518615722656, -0.9982695579528809]
    // this shows up in nearly every FBX file, and generally time array is length > 100

    for (const nodeID in rawCurves) {

      const animationCurve = {

        id: rawCurves[nodeID].id,
        times: rawCurves[nodeID].KeyTime.a.map(convertFBXTimeToSeconds),
        values: rawCurves[nodeID].KeyValueFloat.a,

      };

      const relationships = connections.get(animationCurve.id);

      if (relationships !== undefined) {

        const animationCurveID = relationships.parents[0].ID;
        const animationCurveRelationship = relationships.parents[0].relationship;

        if (animationCurveRelationship.match(/X/)) {

          curveNodesMap.get(animationCurveID).curves['x'] = animationCurve;

        } else if (animationCurveRelationship.match(/Y/)) {

          curveNodesMap.get(animationCurveID).curves['y'] = animationCurve;

        } else if (animationCurveRelationship.match(/Z/)) {

          curveNodesMap.get(animationCurveID).curves['z'] = animationCurve;

        } else if (animationCurveRelationship.match(/d|DeformPercent/) && curveNodesMap.has(animationCurveID)) {

          curveNodesMap.get(animationCurveID).curves['morph'] = animationCurve;

        }

      }

    }

  }

  // parse nodes in FBXTree.Objects.AnimationLayer. Each layers holds references
  // to various AnimationCurveNodes and is referenced by an AnimationStack node
  // note: theoretically a stack can have multiple layers, however in practice there always seems to be one per stack
  parseAnimationLayers(curveNodesMap) {

    const rawLayers = fbxTree.Objects.AnimationLayer;

    const layersMap = new Map();

    for (const nodeID in rawLayers) {

      const layerCurveNodes = [];

      const connection = connections.get(parseInt(nodeID));

      if (connection !== undefined) {

        // all the animationCurveNodes used in the layer
        const children = connection.children;

        children.forEach(function (child, i) {

          if (curveNodesMap.has(child.ID)) {

            const curveNode = curveNodesMap.get(child.ID);

            // check that the curves are defined for at least one axis, otherwise ignore the curveNode
            if (curveNode.curves.x !== undefined || curveNode.curves.y !== undefined || curveNode.curves.z !== undefined) {

              if (layerCurveNodes[i] === undefined) {

                const modelID = connections.get(child.ID).parents.filter(function (parent) {

                  return parent.relationship !== undefined;

                })[0].ID;

                if (modelID !== undefined) {

                  const rawModel = fbxTree.Objects.Model[modelID.toString()];

                  if (rawModel === undefined) {

                    console.warn('THREE.FBXLoader: Encountered a unused curve.', child);
                    return;

                  }

                  const node = {

                    modelName: rawModel.attrName ? PropertyBinding.sanitizeNodeName(rawModel.attrName) : '',
                    ID: rawModel.id,
                    initialPosition: [0, 0, 0],
                    initialRotation: [0, 0, 0],
                    initialScale: [1, 1, 1],

                  };

                  sceneGraph.traverse(function (child) {

                    if (child.ID === rawModel.id) {

                      node.transform = child.matrix;

                      if (child.userData.transformData) node.eulerOrder = child.userData.transformData.eulerOrder;

                    }

                  });

                  if (!node.transform) node.transform = new Matrix4();

                  // if the animated model is pre rotated, we'll have to apply the pre rotations to every
                  // animation value as well
                  if ('PreRotation' in rawModel) node.preRotation = rawModel.PreRotation.value;
                  if ('PostRotation' in rawModel) node.postRotation = rawModel.PostRotation.value;

                  layerCurveNodes[i] = node;

                }

              }

              if (layerCurveNodes[i]) layerCurveNodes[i][curveNode.attr] = curveNode;

            } else if (curveNode.curves.morph !== undefined) {

              if (layerCurveNodes[i] === undefined) {

                const deformerID = connections.get(child.ID).parents.filter(function (parent) {

                  return parent.relationship !== undefined;

                })[0].ID;

                const morpherID = connections.get(deformerID).parents[0].ID;
                const geoID = connections.get(morpherID).parents[0].ID;

                // assuming geometry is not used in more than one model
                const modelID = connections.get(geoID).parents[0].ID;

                const rawModel = fbxTree.Objects.Model[modelID];

                const node = {

                  modelName: rawModel.attrName ? PropertyBinding.sanitizeNodeName(rawModel.attrName) : '',
                  morphName: fbxTree.Objects.Deformer[deformerID].attrName,

                };

                layerCurveNodes[i] = node;

              }

              layerCurveNodes[i][curveNode.attr] = curveNode;

            }

          }

        });

        layersMap.set(parseInt(nodeID), layerCurveNodes);

      }

    }

    return layersMap;

  }

  // parse nodes in FBXTree.Objects.AnimationStack. These are the top level node in the animation
  // hierarchy. Each Stack node will be used to create a AnimationClip
  parseAnimStacks(layersMap) {

    const rawStacks = fbxTree.Objects.AnimationStack;

    // connect the stacks (clips) up to the layers
    const rawClips = {};

    for (const nodeID in rawStacks) {

      const children = connections.get(parseInt(nodeID)).children;

      if (children.length > 1) {

        // it seems like stacks will always be associated with a single layer. But just in case there are files
        // where there are multiple layers per stack, we'll display a warning
        console.warn('THREE.FBXLoader: Encountered an animation stack with multiple layers, this is currently not supported. Ignoring subsequent layers.');

      }

      const layer = layersMap.get(children[0].ID);

      rawClips[nodeID] = {

        name: rawStacks[nodeID].attrName,
        layer: layer,

      };

    }

    return rawClips;

  }

  addClip(rawClip) {

    let tracks = [];

    const scope = this;
    rawClip.layer.forEach(function (rawTracks) {

      tracks = tracks.concat(scope.generateTracks(rawTracks));

    });

    return new AnimationClip(rawClip.name, -1, tracks);

  }

  generateTracks(rawTracks) {

    const tracks = [];

    let initialPosition = new Vector3();
    let initialRotation = new Quaternion();
    let initialScale = new Vector3();

    if (rawTracks.transform) rawTracks.transform.decompose(initialPosition, initialRotation, initialScale);

    initialPosition = initialPosition.toArray();
    initialRotation = new Euler().setFromQuaternion(initialRotation, rawTracks.eulerOrder).toArray();
    initialScale = initialScale.toArray();

    if (rawTracks.T !== undefined && Object.keys(rawTracks.T.curves).length > 0) {

      const positionTrack = this.generateVectorTrack(rawTracks.modelName, rawTracks.T.curves, initialPosition, 'position');
      if (positionTrack !== undefined) tracks.push(positionTrack);

    }

    if (rawTracks.R !== undefined && Object.keys(rawTracks.R.curves).length > 0) {

      const rotationTrack = this.generateRotationTrack(rawTracks.modelName, rawTracks.R.curves, initialRotation, rawTracks.preRotation, rawTracks.postRotation, rawTracks.eulerOrder);
      if (rotationTrack !== undefined) tracks.push(rotationTrack);

    }

    if (rawTracks.S !== undefined && Object.keys(rawTracks.S.curves).length > 0) {

      const scaleTrack = this.generateVectorTrack(rawTracks.modelName, rawTracks.S.curves, initialScale, 'scale');
      if (scaleTrack !== undefined) tracks.push(scaleTrack);

    }

    if (rawTracks.DeformPercent !== undefined) {

      const morphTrack = this.generateMorphTrack(rawTracks);
      if (morphTrack !== undefined) tracks.push(morphTrack);

    }

    return tracks;

  }

  generateVectorTrack(modelName, curves, initialValue, type) {

    const times = this.getTimesForAllAxes(curves);
    const values = this.getKeyframeTrackValues(times, curves, initialValue);

    return new VectorKeyframeTrack(modelName + '.' + type, times, values);

  }

  generateRotationTrack(modelName, curves, initialValue, preRotation, postRotation, eulerOrder) {

    if (curves.x !== undefined) {

      this.interpolateRotations(curves.x);
      curves.x.values = curves.x.values.map(MathUtils.degToRad);

    }

    if (curves.y !== undefined) {

      this.interpolateRotations(curves.y);
      curves.y.values = curves.y.values.map(MathUtils.degToRad);

    }

    if (curves.z !== undefined) {

      this.interpolateRotations(curves.z);
      curves.z.values = curves.z.values.map(MathUtils.degToRad);

    }

    const times = this.getTimesForAllAxes(curves);
    const values = this.getKeyframeTrackValues(times, curves, initialValue);

    if (preRotation !== undefined) {

      preRotation = preRotation.map(MathUtils.degToRad);
      preRotation.push(eulerOrder);

      preRotation = new Euler().fromArray(preRotation);
      preRotation = new Quaternion().setFromEuler(preRotation);

    }

    if (postRotation !== undefined) {

      postRotation = postRotation.map(MathUtils.degToRad);
      postRotation.push(eulerOrder);

      postRotation = new Euler().fromArray(postRotation);
      postRotation = new Quaternion().setFromEuler(postRotation).invert();

    }

    const quaternion = new Quaternion();
    const euler = new Euler();

    const quaternionValues = [];

    for (let i = 0; i < values.length; i += 3) {

      euler.set(values[i], values[i + 1], values[i + 2], eulerOrder);

      quaternion.setFromEuler(euler);

      if (preRotation !== undefined) quaternion.premultiply(preRotation);
      if (postRotation !== undefined) quaternion.multiply(postRotation);

      quaternion.toArray(quaternionValues, (i / 3) * 4);

    }

    return new QuaternionKeyframeTrack(modelName + '.quaternion', times, quaternionValues);

  }

  generateMorphTrack(rawTracks) {

    const curves = rawTracks.DeformPercent.curves.morph;
    const values = curves.values.map(function (val) {

      return val / 100;

    });

    const morphNum = sceneGraph.getObjectByName(rawTracks.modelName).morphTargetDictionary[rawTracks.morphName];

    return new NumberKeyframeTrack(rawTracks.modelName + '.morphTargetInfluences[' + morphNum + ']', curves.times, values);

  }

  // For all animated objects, times are defined separately for each axis
  // Here we'll combine the times into one sorted array without duplicates
  getTimesForAllAxes(curves) {

    let times = [];

    // first join together the times for each axis, if defined
    if (curves.x !== undefined) times = times.concat(curves.x.times);
    if (curves.y !== undefined) times = times.concat(curves.y.times);
    if (curves.z !== undefined) times = times.concat(curves.z.times);

    // then sort them
    times = times.sort(function (a, b) {

      return a - b;

    });

    // and remove duplicates
    if (times.length > 1) {

      let targetIndex = 1;
      let lastValue = times[0];
      for (let i = 1; i < times.length; i++) {

        const currentValue = times[i];
        if (currentValue !== lastValue) {

          times[targetIndex] = currentValue;
          lastValue = currentValue;
          targetIndex++;

        }

      }

      times = times.slice(0, targetIndex);

    }

    return times;

  }

  getKeyframeTrackValues(times, curves, initialValue) {

    const prevValue = initialValue;

    const values = [];

    let xIndex = -1;
    let yIndex = -1;
    let zIndex = -1;

    times.forEach(function (time) {

      if (curves.x) xIndex = curves.x.times.indexOf(time);
      if (curves.y) yIndex = curves.y.times.indexOf(time);
      if (curves.z) zIndex = curves.z.times.indexOf(time);

      // if there is an x value defined for this frame, use that
      if (xIndex !== -1) {

        const xValue = curves.x.values[xIndex];
        values.push(xValue);
        prevValue[0] = xValue;

      } else {

        // otherwise use the x value from the previous frame
        values.push(prevValue[0]);

      }

      if (yIndex !== -1) {

        const yValue = curves.y.values[yIndex];
        values.push(yValue);
        prevValue[1] = yValue;

      } else {

        values.push(prevValue[1]);

      }

      if (zIndex !== -1) {

        const zValue = curves.z.values[zIndex];
        values.push(zValue);
        prevValue[2] = zValue;

      } else {

        values.push(prevValue[2]);

      }

    });

    return values;

  }

  // Rotations are defined as Euler angles which can have values  of any size
  // These will be converted to quaternions which don't support values greater than
  // PI, so we'll interpolate large rotations
  interpolateRotations(curve) {

    for (let i = 1; i < curve.values.length; i++) {

      const initialValue = curve.values[i - 1];
      const valuesSpan = curve.values[i] - initialValue;

      const absoluteSpan = Math.abs(valuesSpan);

      if (absoluteSpan >= 180) {

        const numSubIntervals = absoluteSpan / 180;

        const step = valuesSpan / numSubIntervals;
        let nextValue = initialValue + step;

        const initialTime = curve.times[i - 1];
        const timeSpan = curve.times[i] - initialTime;
        const interval = timeSpan / numSubIntervals;
        let nextTime = initialTime + interval;

        const interpolatedTimes = [];
        const interpolatedValues = [];

        while (nextTime < curve.times[i]) {

          interpolatedTimes.push(nextTime);
          nextTime += interval;

          interpolatedValues.push(nextValue);
          nextValue += step;

        }

        curve.times = inject(curve.times, i, interpolatedTimes);
        curve.values = inject(curve.values, i, interpolatedValues);

      }

    }

  }

}

// parse an FBX file in ASCII format
class TextParser {

  getPrevNode() {

    return this.nodeStack[this.currentIndent - 2];

  }

  getCurrentNode() {

    return this.nodeStack[this.currentIndent - 1];

  }

  getCurrentProp() {

    return this.currentProp;

  }

  pushStack(node) {

    this.nodeStack.push(node);
    this.currentIndent += 1;

  }

  popStack() {

    this.nodeStack.pop();
    this.currentIndent -= 1;

  }

  setCurrentProp(val, name) {

    this.currentProp = val;
    this.currentPropName = name;

  }

  parse(text) {

    this.currentIndent = 0;

    this.allNodes = new FBXTree();
    this.nodeStack = [];
    this.currentProp = [];
    this.currentPropName = '';

    const scope = this;

    const split = text.split(/[\r\n]+/);

    split.forEach(function (line, i) {

      const matchComment = line.match(/^[\s\t]*;/);
      const matchEmpty = line.match(/^[\s\t]*$/);

      if (matchComment || matchEmpty) return;

      const matchBeginning = line.match('^\\t{' + scope.currentIndent + '}(\\w+):(.*){', '');
      const matchProperty = line.match('^\\t{' + (scope.currentIndent) + '}(\\w+):[\\s\\t\\r\\n](.*)');
      const matchEnd = line.match('^\\t{' + (scope.currentIndent - 1) + '}}');

      if (matchBeginning) {

        scope.parseNodeBegin(line, matchBeginning);

      } else if (matchProperty) {

        scope.parseNodeProperty(line, matchProperty, split[++i]);

      } else if (matchEnd) {

        scope.popStack();

      } else if (line.match(/^[^\s\t}]/)) {

        // large arrays are split over multiple lines terminated with a ',' character
        // if this is encountered the line needs to be joined to the previous line
        scope.parseNodePropertyContinued(line);

      }

    });

    return this.allNodes;

  }

  parseNodeBegin(line, property) {

    const nodeName = property[1].trim().replace(/^"/, '').replace(/"$/, '');

    const nodeAttrs = property[2].split(',').map(function (attr) {

      return attr.trim().replace(/^"/, '').replace(/"$/, '');

    });

    const node = {name: nodeName};
    const attrs = this.parseNodeAttr(nodeAttrs);

    const currentNode = this.getCurrentNode();

    // a top node
    if (this.currentIndent === 0) {

      this.allNodes.add(nodeName, node);

    } else { // a subnode

      // if the subnode already exists, append it
      if (nodeName in currentNode) {

        // special case Pose needs PoseNodes as an array
        if (nodeName === 'PoseNode') {

          currentNode.PoseNode.push(node);

        } else if (currentNode[nodeName].id !== undefined) {

          currentNode[nodeName] = {};
          currentNode[nodeName][currentNode[nodeName].id] = currentNode[nodeName];

        }

        if (attrs.id !== '') currentNode[nodeName][attrs.id] = node;

      } else if (typeof attrs.id === 'number') {

        currentNode[nodeName] = {};
        currentNode[nodeName][attrs.id] = node;

      } else if (nodeName !== 'Properties70') {

        if (nodeName === 'PoseNode') currentNode[nodeName] = [node];
        else currentNode[nodeName] = node;

      }

    }

    if (typeof attrs.id === 'number') node.id = attrs.id;
    if (attrs.name !== '') node.attrName = attrs.name;
    if (attrs.type !== '') node.attrType = attrs.type;

    this.pushStack(node);

  }

  parseNodeAttr(attrs) {

    let id = attrs[0];

    if (attrs[0] !== '') {

      id = parseInt(attrs[0]);

      if (isNaN(id)) {

        id = attrs[0];

      }

    }

    let name = '', type = '';

    if (attrs.length > 1) {

      name = attrs[1].replace(/^(\w+)::/, '');
      type = attrs[2];

    }

    return {id: id, name: name, type: type};

  }

  parseNodeProperty(line, property, contentLine) {

    let propName = property[1].replace(/^"/, '').replace(/"$/, '').trim();
    let propValue = property[2].replace(/^"/, '').replace(/"$/, '').trim();

    // for special case: base64 image data follows "Content: ," line
    //	Content: ,
    //	 "/9j/4RDaRXhpZgAATU0A..."
    if (propName === 'Content' && propValue === ',') {

      propValue = contentLine.replace(/"/g, '').replace(/,$/, '').trim();

    }

    const currentNode = this.getCurrentNode();
    const parentName = currentNode.name;

    if (parentName === 'Properties70') {

      this.parseNodeSpecialProperty(line, propName, propValue);
      return;

    }

    // Connections
    if (propName === 'C') {

      const connProps = propValue.split(',').slice(1);
      const from = parseInt(connProps[0]);
      const to = parseInt(connProps[1]);

      let rest = propValue.split(',').slice(3);

      rest = rest.map(function (elem) {

        return elem.trim().replace(/^"/, '');

      });

      propName = 'connections';
      propValue = [from, to];
      append(propValue, rest);

      if (currentNode[propName] === undefined) {

        currentNode[propName] = [];

      }

    }

    // Node
    if (propName === 'Node') currentNode.id = propValue;

    // connections
    if (propName in currentNode && Array.isArray(currentNode[propName])) {

      currentNode[propName].push(propValue);

    } else {

      if (propName !== 'a') currentNode[propName] = propValue;
      else currentNode.a = propValue;

    }

    this.setCurrentProp(currentNode, propName);

    // convert string to array, unless it ends in ',' in which case more will be added to it
    if (propName === 'a' && propValue.slice(-1) !== ',') {

      currentNode.a = parseNumberArray(propValue);

    }

  }

  parseNodePropertyContinued(line) {

    const currentNode = this.getCurrentNode();

    currentNode.a += line;

    // if the line doesn't end in ',' we have reached the end of the property value
    // so convert the string to an array
    if (line.slice(-1) !== ',') {

      currentNode.a = parseNumberArray(currentNode.a);

    }

  }

  // parse "Property70"
  parseNodeSpecialProperty(line, propName, propValue) {

    // split this
    // P: "Lcl Scaling", "Lcl Scaling", "", "A",1,1,1
    // into array like below
    // ["Lcl Scaling", "Lcl Scaling", "", "A", "1,1,1" ]
    const props = propValue.split('",').map(function (prop) {

      return prop.trim().replace(/^\"/, '').replace(/\s/, '_');

    });

    const innerPropName = props[0];
    const innerPropType1 = props[1];
    const innerPropType2 = props[2];
    const innerPropFlag = props[3];
    let innerPropValue = props[4];

    // cast values where needed, otherwise leave as strings
    switch (innerPropType1) {

      case 'int':
      case 'enum':
      case 'bool':
      case 'ULongLong':
      case 'double':
      case 'Number':
      case 'FieldOfView':
        innerPropValue = parseFloat(innerPropValue);
        break;

      case 'Color':
      case 'ColorRGB':
      case 'Vector3D':
      case 'Lcl_Translation':
      case 'Lcl_Rotation':
      case 'Lcl_Scaling':
        innerPropValue = parseNumberArray(innerPropValue);
        break;

    }

    // CAUTION: these props must append to parent's parent
    this.getPrevNode()[innerPropName] = {

      'type': innerPropType1,
      'type2': innerPropType2,
      'flag': innerPropFlag,
      'value': innerPropValue

    };

    this.setCurrentProp(this.getPrevNode(), innerPropName);

  }

}

// Parse an FBX file in Binary format
class BinaryParser {

  parse(buffer) {

    const reader = new BinaryReader(buffer);
    reader.skip(23); // skip magic 23 bytes

    const version = reader.getUint32();

    if (version < 6400) {

      throw new Error('THREE.FBXLoader: FBX version not supported, FileVersion: ' + version);

    }

    const allNodes = new FBXTree();

    while (!this.endOfContent(reader)) {

      const node = this.parseNode(reader, version);
      if (node !== null) allNodes.add(node.name, node);

    }

    return allNodes;

  }

  // Check if reader has reached the end of content.
  endOfContent(reader) {

    // footer size: 160bytes + 16-byte alignment padding
    // - 16bytes: magic
    // - padding til 16-byte alignment (at least 1byte?)
    //	(seems like some exporters embed fixed 15 or 16bytes?)
    // - 4bytes: magic
    // - 4bytes: version
    // - 120bytes: zero
    // - 16bytes: magic
    if (reader.size() % 16 === 0) {

      return ((reader.getOffset() + 160 + 16) & ~0xf) >= reader.size();

    } else {

      return reader.getOffset() + 160 + 16 >= reader.size();

    }

  }

  // recursively parse nodes until the end of the file is reached
  parseNode(reader, version) {

    const node = {};

    // The first three data sizes depends on version.
    const endOffset = (version >= 7500) ? reader.getUint64() : reader.getUint32();
    const numProperties = (version >= 7500) ? reader.getUint64() : reader.getUint32();

    (version >= 7500) ? reader.getUint64() : reader.getUint32(); // the returned propertyListLen is not used

    const nameLen = reader.getUint8();
    const name = reader.getString(nameLen);

    // Regards this node as NULL-record if endOffset is zero
    if (endOffset === 0) return null;

    const propertyList = [];

    for (let i = 0; i < numProperties; i++) {

      propertyList.push(this.parseProperty(reader));

    }

    // Regards the first three elements in propertyList as id, attrName, and attrType
    const id = propertyList.length > 0 ? propertyList[0] : '';
    const attrName = propertyList.length > 1 ? propertyList[1] : '';
    const attrType = propertyList.length > 2 ? propertyList[2] : '';

    // check if this node represents just a single property
    // like (name, 0) set or (name2, [0, 1, 2]) set of {name: 0, name2: [0, 1, 2]}
    node.singleProperty = (numProperties === 1 && reader.getOffset() === endOffset) ? true : false;

    while (endOffset > reader.getOffset()) {

      const subNode = this.parseNode(reader, version);

      if (subNode !== null) this.parseSubNode(name, node, subNode);

    }

    node.propertyList = propertyList; // raw property list used by parent

    if (typeof id === 'number') node.id = id;
    if (attrName !== '') node.attrName = attrName;
    if (attrType !== '') node.attrType = attrType;
    if (name !== '') node.name = name;

    return node;

  }

  parseSubNode(name, node, subNode) {

    // special case: child node is single property
    if (subNode.singleProperty === true) {

      const value = subNode.propertyList[0];

      if (Array.isArray(value)) {

        node[subNode.name] = subNode;

        subNode.a = value;

      } else {

        node[subNode.name] = value;

      }

    } else if (name === 'Connections' && subNode.name === 'C') {

      const array = [];

      subNode.propertyList.forEach(function (property, i) {

        // first Connection is FBX type (OO, OP, etc.). We'll discard these
        if (i !== 0) array.push(property);

      });

      if (node.connections === undefined) {

        node.connections = [];

      }

      node.connections.push(array);

    } else if (subNode.name === 'Properties70') {

      const keys = Object.keys(subNode);

      keys.forEach(function (key) {

        node[key] = subNode[key];

      });

    } else if (name === 'Properties70' && subNode.name === 'P') {

      let innerPropName = subNode.propertyList[0];
      let innerPropType1 = subNode.propertyList[1];
      const innerPropType2 = subNode.propertyList[2];
      const innerPropFlag = subNode.propertyList[3];
      let innerPropValue;

      if (innerPropName.indexOf('Lcl ') === 0) innerPropName = innerPropName.replace('Lcl ', 'Lcl_');
      if (innerPropType1.indexOf('Lcl ') === 0) innerPropType1 = innerPropType1.replace('Lcl ', 'Lcl_');

      if (innerPropType1 === 'Color' || innerPropType1 === 'ColorRGB' || innerPropType1 === 'Vector' || innerPropType1 === 'Vector3D' || innerPropType1.indexOf('Lcl_') === 0) {

        innerPropValue = [
          subNode.propertyList[4],
          subNode.propertyList[5],
          subNode.propertyList[6]
        ];

      } else {

        innerPropValue = subNode.propertyList[4];

      }

      // this will be copied to parent, see above
      node[innerPropName] = {

        'type': innerPropType1,
        'type2': innerPropType2,
        'flag': innerPropFlag,
        'value': innerPropValue

      };

    } else if (node[subNode.name] === undefined) {

      if (typeof subNode.id === 'number') {

        node[subNode.name] = {};
        node[subNode.name][subNode.id] = subNode;

      } else {

        node[subNode.name] = subNode;

      }

    } else {

      if (subNode.name === 'PoseNode') {

        if (!Array.isArray(node[subNode.name])) {

          node[subNode.name] = [node[subNode.name]];

        }

        node[subNode.name].push(subNode);

      } else if (node[subNode.name][subNode.id] === undefined) {

        node[subNode.name][subNode.id] = subNode;

      }

    }

  }

  parseProperty(reader) {

    const type = reader.getString(1);
    let length;

    switch (type) {

      case 'C':
        return reader.getBoolean();

      case 'D':
        return reader.getFloat64();

      case 'F':
        return reader.getFloat32();

      case 'I':
        return reader.getInt32();

      case 'L':
        return reader.getInt64();

      case 'R':
        length = reader.getUint32();
        return reader.getArrayBuffer(length);

      case 'S':
        length = reader.getUint32();
        return reader.getString(length);

      case 'Y':
        return reader.getInt16();

      case 'b':
      case 'c':
      case 'd':
      case 'f':
      case 'i':
      case 'l':

        const arrayLength = reader.getUint32();
        const encoding = reader.getUint32(); // 0: non-compressed, 1: compressed
        const compressedLength = reader.getUint32();

        if (encoding === 0) {

          switch (type) {

            case 'b':
            case 'c':
              return reader.getBooleanArray(arrayLength);

            case 'd':
              return reader.getFloat64Array(arrayLength);

            case 'f':
              return reader.getFloat32Array(arrayLength);

            case 'i':
              return reader.getInt32Array(arrayLength);

            case 'l':
              return reader.getInt64Array(arrayLength);

          }

        }

        if (typeof fflate === 'undefined') {

          console.error('THREE.FBXLoader: External library fflate.min.js required.');

        }

        const data = fflate.unzlibSync(new Uint8Array(reader.getArrayBuffer(compressedLength))); // eslint-disable-line no-undef
        const reader2 = new BinaryReader(data.buffer);

        switch (type) {

          case 'b':
          case 'c':
            return reader2.getBooleanArray(arrayLength);

          case 'd':
            return reader2.getFloat64Array(arrayLength);

          case 'f':
            return reader2.getFloat32Array(arrayLength);

          case 'i':
            return reader2.getInt32Array(arrayLength);

          case 'l':
            return reader2.getInt64Array(arrayLength);

        }

      default:
        throw new Error('THREE.FBXLoader: Unknown property type ' + type);

    }

  }

}

class BinaryReader {

  constructor(buffer, littleEndian) {

    this.dv = new DataView(buffer);
    this.offset = 0;
    this.littleEndian = (littleEndian !== undefined) ? littleEndian : true;

  }

  getOffset() {

    return this.offset;

  }

  size() {

    return this.dv.buffer.byteLength;

  }

  skip(length) {

    this.offset += length;

  }

  // seems like true/false representation depends on exporter.
  // true: 1 or 'Y'(=0x59), false: 0 or 'T'(=0x54)
  // then sees LSB.
  getBoolean() {

    return (this.getUint8() & 1) === 1;

  }

  getBooleanArray(size) {

    const a = [];

    for (let i = 0; i < size; i++) {

      a.push(this.getBoolean());

    }

    return a;

  }

  getUint8() {

    const value = this.dv.getUint8(this.offset);
    this.offset += 1;
    return value;

  }

  getInt16() {

    const value = this.dv.getInt16(this.offset, this.littleEndian);
    this.offset += 2;
    return value;

  }

  getInt32() {

    const value = this.dv.getInt32(this.offset, this.littleEndian);
    this.offset += 4;
    return value;

  }

  getInt32Array(size) {

    const a = [];

    for (let i = 0; i < size; i++) {

      a.push(this.getInt32());

    }

    return a;

  }

  getUint32() {

    const value = this.dv.getUint32(this.offset, this.littleEndian);
    this.offset += 4;
    return value;

  }

  // JavaScript doesn't support 64-bit integer so calculate this here
  // 1 << 32 will return 1 so using multiply operation instead here.
  // There's a possibility that this method returns wrong value if the value
  // is out of the range between Number.MAX_SAFE_INTEGER and Number.MIN_SAFE_INTEGER.
  // TODO: safely handle 64-bit integer
  getInt64() {

    let low, high;

    if (this.littleEndian) {

      low = this.getUint32();
      high = this.getUint32();

    } else {

      high = this.getUint32();
      low = this.getUint32();

    }

    // calculate negative value
    if (high & 0x80000000) {

      high = ~high & 0xFFFFFFFF;
      low = ~low & 0xFFFFFFFF;

      if (low === 0xFFFFFFFF) high = (high + 1) & 0xFFFFFFFF;

      low = (low + 1) & 0xFFFFFFFF;

      return -(high * 0x100000000 + low);

    }

    return high * 0x100000000 + low;

  }

  getInt64Array(size) {

    const a = [];

    for (let i = 0; i < size; i++) {

      a.push(this.getInt64());

    }

    return a;

  }

  // Note: see getInt64() comment
  getUint64() {

    let low, high;

    if (this.littleEndian) {

      low = this.getUint32();
      high = this.getUint32();

    } else {

      high = this.getUint32();
      low = this.getUint32();

    }

    return high * 0x100000000 + low;

  }

  getFloat32() {

    const value = this.dv.getFloat32(this.offset, this.littleEndian);
    this.offset += 4;
    return value;

  }

  getFloat32Array(size) {

    const a = [];

    for (let i = 0; i < size; i++) {

      a.push(this.getFloat32());

    }

    return a;

  }

  getFloat64() {

    const value = this.dv.getFloat64(this.offset, this.littleEndian);
    this.offset += 8;
    return value;

  }

  getFloat64Array(size) {

    const a = [];

    for (let i = 0; i < size; i++) {

      a.push(this.getFloat64());

    }

    return a;

  }

  getArrayBuffer(size) {

    const value = this.dv.buffer.slice(this.offset, this.offset + size);
    this.offset += size;
    return value;

  }

  getString(size) {

    // note: safari 9 doesn't support Uint8Array.indexOf; create intermediate array instead
    let a = [];

    for (let i = 0; i < size; i++) {

      a[i] = this.getUint8();

    }

    const nullByte = a.indexOf(0);
    if (nullByte >= 0) a = a.slice(0, nullByte);

    return LoaderUtils.decodeText(new Uint8Array(a));

  }

}

// FBXTree holds a representation of the FBX data, returned by the TextParser ( FBX ASCII format)
// and BinaryParser( FBX Binary format)
class FBXTree {

  add(key, val) {

    this[key] = val;

  }

}

// ************** UTILITY FUNCTIONS **************

function isFbxFormatBinary(buffer) {

  const CORRECT = 'Kaydara\u0020FBX\u0020Binary\u0020\u0020\0';

  return buffer.byteLength >= CORRECT.length && CORRECT === convertArrayBufferToString(buffer, 0, CORRECT.length);

}

function isFbxFormatASCII(text) {

  const CORRECT = ['K', 'a', 'y', 'd', 'a', 'r', 'a', '\\', 'F', 'B', 'X', '\\', 'B', 'i', 'n', 'a', 'r', 'y', '\\', '\\'];

  let cursor = 0;

  function read(offset) {

    const result = text[offset - 1];
    text = text.slice(cursor + offset);
    cursor++;
    return result;

  }

  for (let i = 0; i < CORRECT.length; ++i) {

    const num = read(1);
    if (num === CORRECT[i]) {

      return false;

    }

  }

  return true;

}

function getFbxVersion(text) {

  const versionRegExp = /FBXVersion: (\d+)/;
  const match = text.match(versionRegExp);

  if (match) {

    const version = parseInt(match[1]);
    return version;

  }

  throw new Error('THREE.FBXLoader: Cannot find the version number for the file given.');

}

// Converts FBX ticks into real time seconds.
function convertFBXTimeToSeconds(time) {

  return time / 46186158000;

}

const dataArray = [];

// extracts the data from the correct position in the FBX array based on indexing type
function getData(polygonVertexIndex, polygonIndex, vertexIndex, infoObject) {

  let index;

  switch (infoObject.mappingType) {

    case 'ByPolygonVertex' :
      index = polygonVertexIndex;
      break;
    case 'ByPolygon' :
      index = polygonIndex;
      break;
    case 'ByVertice' :
      index = vertexIndex;
      break;
    case 'AllSame' :
      index = infoObject.indices[0];
      break;
    default :
      console.warn('THREE.FBXLoader: unknown attribute mapping type ' + infoObject.mappingType);

  }

  if (infoObject.referenceType === 'IndexToDirect') index = infoObject.indices[index];

  const from = index * infoObject.dataSize;
  const to = from + infoObject.dataSize;

  return slice(dataArray, infoObject.buffer, from, to);

}

const tempEuler = new Euler();
const tempVec = new Vector3();

// generate transformation from FBX transform data
// ref: https://help.autodesk.com/view/FBX/2017/ENU/?guid=__files_GUID_10CDD63C_79C1_4F2D_BB28_AD2BE65A02ED_htm
// ref: http://docs.autodesk.com/FBX/2014/ENU/FBX-SDK-Documentation/index.html?url=cpp_ref/_transformations_2main_8cxx-example.html,topicNumber=cpp_ref__transformations_2main_8cxx_example_htmlfc10a1e1-b18d-4e72-9dc0-70d0f1959f5e
function generateTransform(transformData) {

  const lTranslationM = new Matrix4();
  const lPreRotationM = new Matrix4();
  const lRotationM = new Matrix4();
  const lPostRotationM = new Matrix4();

  const lScalingM = new Matrix4();
  const lScalingPivotM = new Matrix4();
  const lScalingOffsetM = new Matrix4();
  const lRotationOffsetM = new Matrix4();
  const lRotationPivotM = new Matrix4();

  const lParentGX = new Matrix4();
  const lParentLX = new Matrix4();
  const lGlobalT = new Matrix4();

  const inheritType = (transformData.inheritType) ? transformData.inheritType : 0;

  if (transformData.translation) lTranslationM.setPosition(tempVec.fromArray(transformData.translation));

  if (transformData.preRotation) {

    const array = transformData.preRotation.map(MathUtils.degToRad);
    array.push(transformData.eulerOrder);
    lPreRotationM.makeRotationFromEuler(tempEuler.fromArray(array));

  }

  if (transformData.rotation) {

    const array = transformData.rotation.map(MathUtils.degToRad);
    array.push(transformData.eulerOrder);
    lRotationM.makeRotationFromEuler(tempEuler.fromArray(array));

  }

  if (transformData.postRotation) {

    const array = transformData.postRotation.map(MathUtils.degToRad);
    array.push(transformData.eulerOrder);
    lPostRotationM.makeRotationFromEuler(tempEuler.fromArray(array));
    lPostRotationM.invert();

  }

  if (transformData.scale) lScalingM.scale(tempVec.fromArray(transformData.scale));

  // Pivots and offsets
  if (transformData.scalingOffset) lScalingOffsetM.setPosition(tempVec.fromArray(transformData.scalingOffset));
  if (transformData.scalingPivot) lScalingPivotM.setPosition(tempVec.fromArray(transformData.scalingPivot));
  if (transformData.rotationOffset) lRotationOffsetM.setPosition(tempVec.fromArray(transformData.rotationOffset));
  if (transformData.rotationPivot) lRotationPivotM.setPosition(tempVec.fromArray(transformData.rotationPivot));

  // parent transform
  if (transformData.parentMatrixWorld) {

    lParentLX.copy(transformData.parentMatrix);
    lParentGX.copy(transformData.parentMatrixWorld);

  }

  const lLRM = lPreRotationM.clone().multiply(lRotationM).multiply(lPostRotationM);
  // Global Rotation
  const lParentGRM = new Matrix4();
  lParentGRM.extractRotation(lParentGX);

  // Global Shear*Scaling
  const lParentTM = new Matrix4();
  lParentTM.copyPosition(lParentGX);

  const lParentGRSM = lParentTM.clone().invert().multiply(lParentGX);
  const lParentGSM = lParentGRM.clone().invert().multiply(lParentGRSM);
  const lLSM = lScalingM;

  const lGlobalRS = new Matrix4();

  if (inheritType === 0) {

    lGlobalRS.copy(lParentGRM).multiply(lLRM).multiply(lParentGSM).multiply(lLSM);

  } else if (inheritType === 1) {

    lGlobalRS.copy(lParentGRM).multiply(lParentGSM).multiply(lLRM).multiply(lLSM);

  } else {

    const lParentLSM = new Matrix4().scale(new Vector3().setFromMatrixScale(lParentLX));
    const lParentLSM_inv = lParentLSM.clone().invert();
    const lParentGSM_noLocal = lParentGSM.clone().multiply(lParentLSM_inv);

    lGlobalRS.copy(lParentGRM).multiply(lLRM).multiply(lParentGSM_noLocal).multiply(lLSM);

  }

  const lRotationPivotM_inv = lRotationPivotM.clone().invert();
  const lScalingPivotM_inv = lScalingPivotM.clone().invert();
  // Calculate the local transform matrix
  let lTransform = lTranslationM.clone().multiply(lRotationOffsetM).multiply(lRotationPivotM).multiply(lPreRotationM).multiply(lRotationM).multiply(lPostRotationM).multiply(lRotationPivotM_inv).multiply(lScalingOffsetM).multiply(lScalingPivotM).multiply(lScalingM).multiply(lScalingPivotM_inv);

  const lLocalTWithAllPivotAndOffsetInfo = new Matrix4().copyPosition(lTransform);

  const lGlobalTranslation = lParentGX.clone().multiply(lLocalTWithAllPivotAndOffsetInfo);
  lGlobalT.copyPosition(lGlobalTranslation);

  lTransform = lGlobalT.clone().multiply(lGlobalRS);

  // from global to local
  lTransform.premultiply(lParentGX.invert());

  return lTransform;

}

// Returns the three.js intrinsic Euler order corresponding to FBX extrinsic Euler order
// ref: http://help.autodesk.com/view/FBX/2017/ENU/?guid=__cpp_ref_class_fbx_euler_html
function getEulerOrder(order) {

  order = order || 0;

  const enums = [
    'ZYX', // -> XYZ extrinsic
    'YZX', // -> XZY extrinsic
    'XZY', // -> YZX extrinsic
    'ZXY', // -> YXZ extrinsic
    'YXZ', // -> ZXY extrinsic
    'XYZ', // -> ZYX extrinsic
    //'SphericXYZ', // not possible to support
  ];

  if (order === 6) {

    console.warn('THREE.FBXLoader: unsupported Euler Order: Spherical XYZ. Animations and rotations may be incorrect.');
    return enums[0];

  }

  return enums[order];

}

// Parses comma separated list of numbers and returns them an array.
// Used internally by the TextParser
function parseNumberArray(value) {

  const array = value.split(',').map(function (val) {

    return parseFloat(val);

  });

  return array;

}

function convertArrayBufferToString(buffer, from, to) {

  if (from === undefined) from = 0;
  if (to === undefined) to = buffer.byteLength;

  return LoaderUtils.decodeText(new Uint8Array(buffer, from, to));

}

function append(a, b) {

  for (let i = 0, j = a.length, l = b.length; i < l; i++, j++) {

    a[j] = b[i];

  }

}

function slice(a, b, from, to) {

  for (let i = from, j = 0; i < to; i++, j++) {

    a[j] = b[i];

  }

  return a;

}

// inject array a2 into array a1 at index
function inject(a1, index, a2) {

  return a1.slice(0, index).concat(a2).concat(a1.slice(index));

}

export {FBXLoader};
